Electron discharge device of the cavity resonator type



-Aug. 9, 1949.

Filed Dec. 13, 1944 O Aug. 9 1949. l EL N. KATHER I 2,478,534

Filed Dec 13, 1944 ELECTRON DISCHARGE DEVICE OF THE v CAVITY RESONATOR TYPE 2 Sheets-Sheet 2 Patented Aug. 9, 1949 CAVITY RESONATOR TYPE` Erich Nevin Kamer,- south Lincoln, Mass., as- ,Y

signor to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application December 13, 1944, Serial No. 568,008 v 13 Claims.

This invention relates to electron discharge devices havin-g a plurality of resonant Ycavities or cavity resonators for generating high frequency oscillations, and more particularly to those for generating ultra-short wave oscillations. As the wave length is determined by the size ofthe cavity, if it is desired to increase the power of the device without increasing the wave length, it is necessary to increase the number of the cavities. Experience has shown, however, that merely increasing the number of the cavities, if carried beyond a certain point, may result in the produc-v tion of objectionable phenomena, for example the generation of spurious oscillations and a decrease in the ratio of the energy actually delivered by the device to that actually generated, very little if iany of the energy generated in the cavities remote from the cavity containing the f usual output coupling loop or other coupling device ever reaching the said coupling device.

One of the. objects of the present invention is to provide an improved electron discharge device of the general type above referred to, wherein the increased number ofV cavities requiredto deliver the power desired without vincreasing the Wave length may be provided without giving rise tothe aforesaid `objectionable phenomena.

-Another object of the present invention is to provide an electron discharge device of the general type referred to having an improved symmetrical coupling for all of the cavity resonators, by which the ratio of energy actually delivered to that generated by the device is materially increased.

These objects and such other aims and objects of the present invention as may hereinafter appear will be best understood from the following description,.taken in connection with the accompanying drawing of one embodiment of the inventionA hereinv presented for illustrative purposes.

In the drawing:

Fig. lis acentral, longitudinal section of an electron discharge device incorporating one illusf trative embodiment of the invention;

Fig. 2 is a horizontal cross-sectionY on line 2-2 of Fig. 1 on a, somewhat larger scale Athan that The invention is herein illustratively shownV and described in its application to that'type of electron discharge device known as a magnetron. 'f

VThe illustrative embodiment of the invention shown in the drawing comprises an anode structure including a cylindrical member 2 upon the inner surface of which `there is provided a central, cylindrical projection 4 to which are soldered a plurality of suitably spaced, radally disposedA anode arms 6, the inner ends of which constitute electron-receiving anode faces 8. Each pair of anode arms 6, with the intervenngportion of said cylindrical .projection 4, constitute an oscillatory cavity or cavity resonator IU. (See Fig. 2.) Said cylindrical member 2 is -hermetically sealed at both ends by suitable means, thus vconstituting an hermetically sealed envelope. In the illustrative embodiment of the invention shown, pole pieces I2 and I 4, serving as hereinafter more fully explainedzto excite a longitudinal magnetic field in the device, are conveniently used for this purpose. These pole pieces I2 and I4 conveniently comprise a conical portion I6 and a central, cylindrical portion I8 provided with a central, 'cylindrical bore 20. Said conical-portions .I6 of said twopole pieces I2 and Ill project into opposite ends, respectively, of said cylindrical member 2,

the conical'surface of each pole piece being encircled by a slot 22 rectangular in cross-section and fitting over the inner, rectangular edge of v the inner -wall of said cylindrical member 2 to Whichit is soldered, preferably with silver solder, thus completing the hermetical sealing of the enclosure. lSaid cylindrical member 2 and anode arms 6will preferablyv bemade of coppensaid anode arms being conveniently stamped from a sheet of highly conductive copper. The surface ofthe central cylindrical bore20 of the pole piece I2 is copper-plated to render it electrically con-J The aforesaid anode faces 8 cooperate with a f cathode 24 supported substantially centrally ofA said anode faces, said cathode being preferably of the indirectly-heated, thermionic type., 'It

comprises a conductive wall 24 of nickel or'other suitable conductive material, preferably coated with an electron-emissive coating 26 of barium Y and strontium oxide or other suitableelectrono emissive material, and contains a helically wound y heater Wire 28 of tungsten or other suitable metal f connected at one end to the inner surface of the l conductive Wall 24 of the cathode, the other end being connected to a lead-in conductor 29 of molybdenum or other suitable metal sealed through a` glass bead 3!! in the outer end of a conductive sleeve 32 of suitable sealing metal embraced in a further conductive sleeve 34, preferably of copper alloy, which supports the cathode 24.`Y Said sleeve 34 is sealed through cup 36 of suitablev sealing metal; A further sleeve 36'-, in

Herein they are conveniently made integral witlilloxfsyrnmetrical coupling.

the cathode wall.

If the device above described beenergi-zedfandf the pole pieces I2 and lli be also energized with a magnetic eld supplied from an:externalfielec-r:-V

15 device tromagnet or permanent mag-'net orfotherfsuit able means, oscillations will besetup` insaid-ecavities l0. In accordance witnrthezcpresent inea- Vention the energy thus developed in said cavities is led out in the following novel manner: Altere 4 onequarter Wave length, will preferably be provided in said pole piece l2. Preferably also a hollow, thin-walled horizontally corrugated section 52 of copper with a small vent 64 will be 5 provided in the copper center conductor All to allow for any longitudinal expansion and contractionof the rl'atter responsive'Y to variations in temperature- The present invention provides a system of It couples into all the resonant-cavities.-equally, so that the ratio of energy-absorbed and delivered to that generated by all the cavities is increased. Using both strapsualsosaddsl toifthe efficiency of the present Wherever"the-expression a plurality occurs it.risstoabewconstrued.as meaning two or more.

l' am aware 'that the present invention can be embedie'dcin other specific forms without departnate anode arms l are electrically connected by 20 from the spirit or essential attributes thereof,

suitablek 'means' at: their. upper ends;A viewin g.: Fig toi-the?=inner=1endfof Aa conductor lllfiioflcopperf.on; otheru suitable' iconduetivef metal-',:coainalf with ther: cathodefandsealed through a glass:sealudisealed':

and l. .therefore` desirfetheipresent Adescription to bei considered in all respects i as. illustrative and notfrestrictive, #reference :being had f `,to :itheapi' l pentledlaims ratherhthan :to theffaoresaid detoionelendlofa sealingftub'eil of suitablelsealinggz25- scription toiindicate'vthe scopeofthe. invention-1l metalgtli'e. other'end'fofrifwhich. is zbrazedgto'i the: innere andi-upper end .of thel Cylindricalrportion rl 8 of-fsa-id polepiecewl 2i The intervening. anodearmsr: tjbetweenffthose eonnectedlto said 'conductor :Mg: -f

'vvl'iatzislclaimedisz i 1.1An electroni'discharger domed-comprising a cathodeg-an AanodeL structureV includingaa plurality orfanode `-arms "hat/ing. electronereceiving por# aye-lelecmiggyuyisconnectedfbyfsuitable means-tat;;30ltions adjacentisaid.cathodean'd constitutingveletheir iupper A:ends ,to the lower -end1 of :said pole; piece V@I 2;5-2; In' thai-illustrative embodiment of. .the-i inventionshown?theconnectionf=ofzther alternate@ anode farms J6 withsaidiconducton llftiis-conven--f` ments of 'energyrgenerating cavitytresonatorsim l terconnectin'g said electroni-receiving portions, an i inner-fand an. outerfelec-tricaliy- ,conductive strap, s the.: one.- ffelectrically @interconnecting 's alternateff iently eiectedbyY an ele'ctricallyrfconductive' mem, 35 i* anodelarmsziand 'thetiptherf electrically... intercorre beiefsuch-as-la circular cap comprising a sdis'c. 5 hav-ingta'downwardly projectingzfflangeflSZ con. i centrici withfthef cathodeilM!and` solderedtos-said alternate .anode arms'fthe lower; end .of said con-a.,

nectingrrthez interveningzanode arms;l and` anout-1 putf-couplirigrginc'ludingxsaidftwoistraps .fasga 'partiT thereof.` i .Y

2 l An.;.-electron: discharge? devicescomprising: a

ductorfq 4 @being some1-edlenthlenter -Of said ,diga f lo tcathodeyzarr fanodeistructure .includingxa plurality` 50235" TheL connecti'nwof: itlc-eirsarnewends Volf-ther-r intervening' anodel` arms;.'\':betw-eenMy lthosecon-1: nectedhtosai'dllconductorli, isl convenientlyfmadeff lay-an i electrically? conductive mei-uber, such las-11 soldered-i at C'one fendi `to ilsaid lintervening anode arms and-#ati the" other fen-d Atol saidipole oie'ce'f` l 2-.'`

y A 'metallstrap ifinterconnects `thefothr- 'endsi oftliose anode'armsl whose--upper-ends are con-r.-

neoted to'said#conductor-44fand'^anothr strapftitcoaxial conductorss and'fsa [secondaY electrically# of 1' anodesrarms;shavingelectronereceiving fportions' adj acentf said,cathoderand;constitutingsele` ments. :ofi energy 'generating :cavity resonatorstin-z te-rconI-Iectirigz-esaidy i:electrolrireeen/inge portions;

by the devicezoutzof lth'e'"latter;:anaelectri'cally con-'fi` cluctiiezi-strap::interconnecting: alter-hateni anode armsilian'ct electrica'ily'connectedftoione; of said i' conductivefstrap; :interconnectingzthe 'intervene l ingfalio det'armssand electrically connected to' said,x l other fcoaaialrconductor.

3. An electron discharge device comprisinga strap 58, at the other end of the anode structure, @Mercat-houle; ananode: structure including-e vpllllly not only Y 'pe1:form ther-function flheretofore performedeby--ordinary `strappi-ngfofdecreasing any tei'ileiicy"A of #ther-device vto operate v:in-1 spurious 1 modes-but theeconnection f of -saidsla'nge'- S25-"and 1 or anode arms;having electron-receiving .portions adjfaccntzsaidt' cathode?- and- .constituting elex'nents of i energy r generating cavity r4resonators .intercon-A necting :xsaidi electron-freceivingportions; centerven-ientlylfconsistingfoffsaidf-pole piece l Zwhence e it can LbeA suppliedf to *any desired utilizingfcircui-t f through any-'conventional `"wave guidel Forfthe .i

begtnfesuls fl-,h-ndimensions @f fsad :Coaxial une fmcathode, an anode structure including a plurality a, suitablnzehoken-fsuclri asta -circularslot` :6 lln'of :,fmiandnouteracoaxial :conduntorsrfiorming: a ,coaxialc line for conducting oscillations generated by-'the device out of the latter, an electricallyl'condu'ctives: circular @cap f-interconn'ectin'g alternate anode armsziandrconnoctedif atfitsfcenter to-the centerv r byhsaid Center,Conductowweandva vSuitable- Outer nnoaxial conductoryrandzanelectrically conductive f circ-ul ar flsle'eveinterconnecting the intervening anode arms 'sand electricallyficonnected -toJa-thel outer coaxial conductor.

4. -Anfelectronzrlischarge rdevicef comprising Va of-anode armsihazv-ing electron-receiving.portions adjacents said lcathodep'and constituting elements "enterz'and'iouter scon'chictors'vforming :a 1 coaxiafllliiref for;conducting` oscillationslgenerated "line for conducting oscillations generated by` the device out of the latter, an electrically conductive circular cap and an electrically conductive sleeve Acoaxial therewith at one end of said anode, said l circular cap being connected centrally to said cen- 'j ter coaxial conductor and to alternate anode arms, and said electrically conductive sleeve being connected to said outer coaxial conductor and to envelope hermetically sealed at both ends by polev pieces and containing a cathode,an anode includinga plurality of anode arms having electronvreceiving portions adjacentjsaid cathode and yconstituting elements of energy generating cavity resonators interconnecting said electron-receiving portions, an inner and an outer electrically conductive strap at each end of said anode structure, alternate and intervening anode arms being interconnected at one end, of said anode by the vinner and Vouter strap,'respectively, andatthe 'other end bythe outer and the innerv strap, respectively, the innerstrap and outer strap at one end of the anode structure being electrically connected, the former to a conductor extending axially through a bore inone of said pole pieces and the latter to said pole piece, which is electrically conductive, said conductor and 'said pole piece forming the center conductor and the outer conductor, respectively, of a coaxial line through which oscillations generated by the device may be conducted out of the device.

6. An electron discharge device comprising an envelope hermetically sealed at its ends by pole pieces and containing a cathode, an anode structure including a plurality of anode arms having electron-receiving portions adjacent said cathode and constituting elements of energy generating cavity resonators interconnecting said electronreceiving portions, electrically conductive straps interconnecting the alternate anode armsand the intervening anode arms, respectively, at each end of said anode, the strap interconnecting the alternate anode arms and the strap interconnecting the intervening anode arms at one end of said anode being electrically connected respectively to a conductor extending axially through a bore provided in one of said pole pieces and to said pole piece which is electrically conductive, said conductor and said pole piece forming the center conductor and the outer conductor, respectively, of a coaxial line through which oscillations generated by the device may be conducted out of the device.

'7. An electron discharge device comprising a cathode, an anode structure including a plurality of anode arms having electron-receiving portions adjacent said cathode and constituting elements of energy generating cavity resonators interconnecting said electron-receiving portions, coaxial center and outer conductors forming a coaxial line for conducting oscillations generated by the device out of the latter, and output coupling means at one end of said anode incorporating an inner conductive strap interconnecting alternate anode arms and electrically connected to said center conductor and an outer electrically conductive strap interconnecting the intervening 'anodearmsj` and electrically connected to said outer conductor. y

' 8. An velectron discharge device comprising a cathode, an anodestructure including a plurality of anode arms having electron-receiving portions adjacent said cathode and constituting elements of energy generating cavity resonators interconnecting said'electron-receiving portions, coaxial center and outer conductors forming a coaxial line for conducting oscillations generatedV by the device outof the latter, output coupling means at one end of said anode incorporating an inner conductive strap electrically interconnecting alternate anode arms and electrically connected to said center conductor, and an outer electrically conductive strap interconnecting the intervening anode arms and electrically connected to said outer conductor, and at the other end'ofV said anode structure an outer electrically conductive strap interconnecting said alternate anode arms, and an inner electrically conductive strap interconnecting said intervening anode arms.

y 9. Anv electron discharge device comprising a cathode, anl anode structure including a plurality of anode arms having electron-receiving portions adjacent said cathode and constituting elements of 'energy generating cavity resonators interconnecting said electron-receiving portions, a coaxial line for conducting oscillations generated by the device out of the'latter and incorporating an electrically conductive pole piece and a center conductor extending axially of a bore provided in said pole piece, and output coupling means incorporating an inner and an outer electrically conductive strap, said inner conductive strap interconnecting alternate anode arms and being electrically conected to said center conductor, and said outer electrically conductive strap being electrically connected to said pole piece and interconnecting said intervening anode arms.

10. An electron discharge device comprising a catho-de, an anode structure including a plurality of anode arms having electron-receiving portions adjacent said cathode and constituting elements of energy generating cavity resonators V interconnecting said electron-receiving portions,

a icoaxial line for conducting oscillations generated by the device out of the latter and consisting of an outer conductor and a center conductor extending axially of a bore provided Vin said outer conductor, output coupling means at one end of said anode structure incorporating an inner and an outer electrically conductive strap, said inner conductive strap interconnecting the alternate anode arms and being electrically connected to said center conductor, and said outer electrically conductive strap being connected to said outer conductor and interconnecting the intervening anode arms, and an inner and an outer electrically conductive strap at the other end of said anode s-tructure, the former interconnecting said alternate anode arms and the latter interconnecting said intervening anode arms.

11. An electron discharge device comprising a cathode, an anode structure including a plurality of anode arms surrounding said cathode and having electron-receiving portions adjacent said cathode and constituting elements of energy generating cavity yresonators interconnecting said electron-receiving portions, coaxial center and outer conductors forming a coaxial line for conducting oscillations generated by the device out of the latter, output coupling means incorporating atci-rcular electricallyconductiveA member interconnecting alternate anode armsand connected at its -center to -saidcenterA conductor, and a second electrically -conductive circular member coaxial withsaid rstenamed-member and interconnecting the,interveninganodev arms and .electrically connected-.to said .outer conductor.

A -12.,An electron v.discharge dev-ice comprising a -cathoda ananodestructure including a Splu- Yralitymf anodearms surroundingfsaid cathode and having lelectron-receiving. portions adjacent said cathode and'constituting elements.V ofenergy generating cavity resonators interconnectingv said `electron-receiving portions, coaxial centerand ,outerconductors forming acoaxialline for conducting. oscillations vgenerated by the device r.out of the latter, 4output coupling means incorporating a circular electrically conductivamember .interconnecting alternate Yarms `,at one, end of saidancde structure and connected at itsfcenter to said centerconductor, a second electrically conductive circular, member coaxial with said `rstnamed. member and ,interconnecting fthe., intervening anode armsatthe sameend of said anode .structure and electrically connected to said outer conductor, and an outer and arrinner electrically conductive strap at the other 4end of said anode =str ucture interconnecting the alternate and the intervening anode arms, respectively.

13. An electron discharge device comprising: a cathode, an anode structure including a plurality of anode arms having electron-receiving portions adjacent saidv cathode and constituting elements of energy generating cavity resonators inter- 'alternate anode arms, and said electrically conductive sleeve being connected to said outer coaxial conductor and to intervening anode arms.

ERICH NEVIN-KATHER.

REFERENCES CITED Thefollowing `references are of record in :the ille o this patent:

' UNITED STATES PATENTS Number Name Y Date V2,147,159 -Gutton et al. Feb. 14, 1939 V2,242,838 Hollmann May20,A 1941 2,414,084 Bowen Jan. 14,1947 2,414,085 Hartman ,Jan. 14, 1947 2,418,117 Hale et a1 Apr. 1, 1947 2,418,469 Hagstruni Apr, 8, 1947 2,419,572 Liaco et al Apr. 29, 1947 2,422,465 Bondley June 17, 1947 "2,424,496 Nelson July 22, 1947 FOREIGN PATENTS YNumber Country Date 445,084 GreatBritain Apr. 2, 1936 509,102 Great Britain July 11,1939 515,229 Great Britain Nov. 29, 1939 

